Radially cutting tube cutter having adjustable tool



May 1 1956 w. F. OBERHUBER ETAL 2743521 RADIALLY CUTTING TUBE CUTTERHAVING ADJUSTABLE TOOL filed July 29, 1955 2 sheets-sheet 1 5.5i? i7 253 3/ ,ya e.;

May 1, 1956 w. F. OBERHUBER ET AL. 2,743,521

RADIALLY CUTTING TUBE CUTTER HAVING ADJUSTABLE TOOL 2,743,521zR'lIiIJIIY CUTTING TUBE 'CUTTER HAV ING -DJUSTABLE TOOL i `William F."berhliber fand .Erne'st Wollim Philadelphia, 'and lfredfl. Goetz'e,*Huntingdon Valley, Pa. fApplcationJuly 29, 1953, Serial No. 370,9722'ClaimS. (Cl. 30-8-106) "The Apresent invention 'relates AIto `cutters`for condenser, "co'o'ler and heatexchangertubes. Apurpose o'ftheinvention is Vto obtain more 'positive action and particularly to obtainv'rnorepositive release 'of the cutter y"from the "tube after cutting.

A f'fu'rt'he'r purpose is to make a lighter, smaller 'and simplertbercu'tter.

`Affurtherpurposeis to speed up the cutting action and iappear,selecting -t'helforms shown from 'the standpints-of :convenienceiniillustrati'on, satisfactory operation andclear I*demonstrationrof'the.principles involved.

Figure '.liis aflongitudinaltsectionfofithe preferred cutter ."of the:invention 1in fretraete'd position.

Figure 2 is a view corresponding to Figure l showing 'thecutter'adv'anced to'cutting position.

fFigure 'B isa :longitudinal Vsection Ion the line 3 3 'of iEigLlIefl.

- Fi'guref'4sis :a freary endelevaton' of thedevice ofFigu'res Figure .5is a staggered rsection 4on 'the 4line "5v-'5 vvof .Figure 1.

Y fFigurefis section onsthelinedotzFigure 1.

:Figures 7 to .14 showavariationfinthe invention.

:Figure .7 -.is a tlongitudinal :section showing .fthe :cutter.'installed, :readyfto `cut a-tube,:but\sti1l retracted.

Figure 8 .is :a view corresponding to Figure .7 showing.thecutter/advancedandthe'tubecut.

Figure 9 lisa Vsectionon the line --9=9 of Figure 7, omit-.tingfthetubeandtubesheet.

4Figure .l-O vis yan enlarged front -view1of-1th`e `cutter'fof `Figuresv7 'to 9.

HFigure 1-1 .is1an enlargedsection on '.theli'ne 11-1=1 of -F-igt 7.,omitting lthe tube. f f

Figure 12 is an enlarged-section on the :line 12-12iof Figure 7. y

Figure 13 is anenlarged section on the line 13-13 of "Figure 7.

Figure 14 is a fragmentary section on the line 1'4--14 of Figure 1l. p

Describing in yillustrationbut n'tin liinitation'and referring to thedrawings:

Tubes in condensers, coolers and other heatexchangers 'areusuallyrolled'into -engagement with-a tubesheet, and

"they'canbeveryquickly installed. It is, however, occasionallynecessaryto remove-and replace such'tubes and` this isla diiicultl operation. In'commonpractice in removin'g the tube, itfiscut vbyfa-tube cutter whichcutsotf `the tube .inside fthe -tube .sheet and thus pe'rmits "thefs'evered ,United States patent@ patent `have several disadvantages.

Pa-tented .May l, .1.956

2 is-an improvement over `tube cuttersof the type disclosed in WilliamF. Oberhuber U. S. :Patent No. 1,922,630, ,grantedAugust .15,1.933,.'for Cutter'for Condenser Tubes.

Cutters -of Athe-character of thatf shown in the Oberhuber Once `thetube is cut thecutter is often `slow inrestoringthe Yparts-to1startingpositiomso that Atherefis delay or -diieultyin Lextracting the cuttingedges. By-thetpresent inventionamore rapid .positive .carn action islapplied to return the cutter to its startingposition to avoid ythisdifficulty. n

In the .prior artl cutters, Athe operation has often .been slow, because`the feed of ithe cutter -has not lbeensuillciently rapid. The ,present.invention is designed :to `rgive more rapid -feed andpreferably :toemploya cutter .separate from the cutter bar which .is 'extending.radially -and can be positioned at `the most advantageous :angle .formaximum xfeed. 5 The device of the invention also is ymarkedly llighter-and 'smaller than prior art cutters.

One of the :features Whichfhas lbeen inherent in prior art cutters is'that a great deal of strength-and energy has been required'inoperation. `Part ofthishas'been due to -thefri`eti`o`nal drag ofthecollar against-the end of the tube. 'In 'thedevi'ce 'of vthe inventionthis has been cutdownby .introducing an a'ntifriction thrust bearing atthis point.

"In '.'some cases obstructions on the inside of '.the'tibe 'mfake "itnecessary 'to 'ream as 'a .separate operation. lIn "one 4ofthelfon'nsof"th'eimfention:a reame'r is mounted 'on "the forward endof 'the'cutter so thatfany--sur'faces requirvving rea'mi'ngwill be Jreame'd asthe'cutter is introduced 'irito the tube.

"Considering, now 'the form 'of Figures "l Lto f6 inclusive, aplug 20"which formsthe main body df "the device Jhas a -forwajrd=portion 21which extendsinto the nibet'ojbe cutan'dis suitably of the'large'stdiameter of the plug, has a'ntintermediate 'portion '2'2"whic`h .issuitably of circular outside contour and'is o'fsrlig'htlyLrleduceddiameter, ,jo'ining Ythe -forward portion "21 :in a stop shoulder 23,and has a rearward shank 24 which is adaptedtobe chucked 40 ina'rotarydrill 'or'oth'er rotary tool operates .the

Cutter.

From'a"position1just"forw'ardof the shank 24, a longitudinal slotJz'sextenusthe full distanceforwardto the front y'olf the 'cutterand is"ad'aptedito contain `the cutter `bar.

Surrounding'theplug andnor'mally engaging the shoul- `der '24 is awasher-like forward thrust bearing race .26 which is movable along "the.plug as shown. Rearwardly ofthe lforward thrust "bearing race 26 andproviding .a rearward thrust bearing "race we place a collar 27 which"moves longitudinally of the plug in operation. To complete the thrustbearing, balls 28 are placed Abetween the 'forwardrace and the collar.The balls lZ8 are heldin place `by aconventional vball retainer "ring'.(not illustrated).

Thecollar is desirably provided with an annular ex- 'ten'sion i3'()directed rearwardly and this vengages the `for- 'ward'end of laspiralcompression vspring 31, the rearward en'd df which isengaged by avspring abutment 32 which surrounds the plug and is adjustable alongf'it .by a set k'scre'w 33. Thusthe'spring tension can be regulated.

`In 5ltheslot y25 'and extending 'forwardly of the collar v'the'reii'satool bar 34 which at"it`s"for'w'a'rd end hasa transverse-'opening 35which receives a vtransverse radially exvtending'cutter 36, :held in"place by set screw-37 which .in

fthe lform of Figures l'to 6 extends longitudinally. As

vshown in Figures 3`t`o 6, the slot^25 is desirably positioned to oneside of the center so that the leading edge of the fcutter`36-is radial.

'The cutter'har nearits rearward end has a pivot ear 38 whichextendsinto a 'slot 40 df the collar. A pin 41 extends acrossthecollar'through an 'opening therein to pivot 4the lcutter-iban In the retractedposition, one face 42 of the cutter bar extends longitudinally along thebase of the slot, but near the forward end behind the cutter a camportion 43 of the cutter bar deviates from the longitudinal line of theface 42 in a direction away from the cutter point, forming a cam surfacewhich on rearward movement of the collar engages a cam surface 44 on theforward end of the slot in the plug to urge the cutter radiallyoutwardly as shown in Figure 2. Rearwardly of the pivot 41 the cutterbar has a cam extension 45 which on the surface 46 extends converginglytoward the bottom of the slot as it moves rearwardly. Pin 47 extendsacross the plug near the base of the slot and when the cutter retractsthe cam surface 46 on the cam extension 45, engages the pin and forcesthe cutter radially inwardly. This therefore gives very effectiveretraction of the cutter. The collar 27 is slotted at 47 to permitinsertion of the pin 47.

In operation of the form of Figures 1 to 6, with the parts in retractedposition and the shank mounted in the chuck of a drill, the forwardportion 21 of the plug and the cutter and the forward part of the cutterbar are inserted in the tube to be cut. When pressure is applied withrotation after starting the electric drill or other tool, the thrustbearing race 26 engages the end of the tube and the thrust bearingpermits rotation of the cutter without serious frictional drag since thefriction is reduced by the bearing balls 28. As the collar movesrearwardly in Figure 2 the engagement between the cam surfaces 43 on thecutter bar and 44 on the plug urge the cutter radially outwardly, andthe tube is cut. When the cutting operation is complete the operatorreleases the pressure and allows the spring 31 to force the collarforward. At this time pin 47 encounters cam surface 46 and positivelyforces the cutter bar to the retracted position.

In the above operation, very rapid feeding is accomplished and this canbe done without damage to the cutter since the cutter is directedradially outwardly and is not merely inclined. Comparatively littlestrength is required because the drag previously experienced between thecollar and the end of the tube is largely avoided.

The forward race 26 of the thrust bearing need not turn and ordinarilywill not.

In the form of Figures 7 to 14 a reamer is provided toc ream any burrsin the same operation, and the reamer is used as one of the cam surfacesto retract the cutter bar. As seen in Figure 7, a tube 48 to be cutextends through a tube sheet 50 and has been rolled at 51 to eugage thetube sheet and anged at 52 at the outer end.

In this form the plug has a forward portion which is of reduced diameterat 53, and receives a tubular reamer 54 which makes a forced t and hasouter tinted portion 55. At a position still inside the tube duringcutting, the forward portion of the plug is enlarged at 56 to form thestop shoulder 23. The thrust bearing including the collar, the springabutment and the spring are suitably the same as in the other form. Theslot extending longitudinally through the plug in this form involves astraight slot portion 57 which extends to a position near thc tool, thena tool feeding cam 58 and then a recess 60 toward the forward end whichallows the tool to move inward.

The tool bar in this form is straight for a considerable distanceforward of the ear 38, but forward of the tool receiving opening whichmounts the radially extending tool 36 there is on the outside aretraction cam 61 which during the retraction engages the inner edge 62of the reamer. The set screw 37 which holds the tool in this caseextends in from the side of the tool bar instead of outside near theforward end of the tool bar engages the inside of the reamer at 62 toretract the tool. The reamer functions during the early stages ofcutting to remove any burrs and allow the cutter to achieve the requiredposition in the tube.

In view of our invention and disclosure variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of ourinvention without copying the structure shown, and we therefore, claimall such insofar as they fall within the reasonable spirit and scope ofour claims.

Having thus described our invention what we claim as new and desire tosecure by Letters Patent is:

l. In a cutter for tubes, a plug having a longitudinal slot, adapted toextend into a tube to be cut, having near its forward end an externalshoulder directed rearwardly and having a shank at the rear adapted tobe received into the chuck of a rotary tool, a forward thrust bearingrace surrounding the plug and normally engaging the shoulder, a collarsurrounding the plug rearwardly of the forward thrust bearing race andforming a rearward thrust bearing race, thrust bearing elements betweenthe forward thrust bearing race and the collar, the collar, forwardthrust bearing race and thrust bearing elements being movable along theplug, a spring abutment adjustably secured to the plug rearwardly of thecollar, a spiral compression spring surrounding the plug and acting between the spring abutment and the collar, a tool bar extendinglongitudinally through the slot and having a tool mounting at itsforward end, a tool secured in the tool mounting and extending radially,a pivot on the collar pivotally mounting the tool bar, cam means at theforward end of the plug acting between the plug and the tool bar to urgethe tool bar outwardly when the collar moves rearwardly, a cam extensionon the tool bar rearwardly of the pivot, and a pin extending across theslot secured to the plug and acting against the cam extension to urgethe tool radially inwardly when the collar moves forward.

2. In a cutter for tubes, a plug having a longitudinal slot, adapted toextend into a tube to be cut, having near its forward end an externalshoulder directed rearwardly and having a shank at the rear adapted tobe received into the chuck of a rotary tool, a forward thrust bearingrace surrounding the plug and normally engaging the shoulder, a collarsurrounding the plug rearwardly of the forward thrust bearing race andforming a rearward thrust bearing race, thrust bearing elements betweenthe forward thrust bearing race and the collar, the collar, forwardthrust bearing race and thrust bearing elements being movable along theplug, a spring abutment on the plug rearwardly of the collar, a spiralcompression spring surrounding the plug and acting between the springabutment and the collar, a tool bar extending longitudinally through theslot and having a tool mounting at its forward end, a tool secured tothe tool mounting and extending radially, a pivot on the collarpivotally mounting the tool bar, and cam means acting between the plugand toolbar to move the tool radially outward in one direction ofrelative movement of the plug and tool bar, and to move the toolradially inward on the opposite direction of relative motion.

References Cited inthe le of this patent UNITED STATES PATENTS 646,907Henrikson Apr. 3, 1900 794,337 Blevins July l1, 1905 872,290 Lusk Nov.26, 1907 1,922,630 Oberhuber Aug. l5, 1933 2,262,041 Pennella e Nov. 11,1941 2,356,402 Haynes Aug. 22, 1944 2,446,734 Armstrong Aug. 10, 1948

